xfs_io: dedupe command should only complain if we don't dedupe anything

The dedupe command should only complain about non-matching extents if
the kernel hasn't managed to dedupe /any/ of the input range.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
diff --git a/io/reflink.c b/io/reflink.c
index 26eb2e3..72dfe32 100644
--- a/io/reflink.c
+++ b/io/reflink.c
@@ -70,7 +70,8 @@
 					_(strerror(-info->status)));
 			goto done;
 		}
-		if (info->status == XFS_EXTENT_DATA_DIFFERS) {
+		if (deduped == 0 &&
+		    info->status == XFS_EXTENT_DATA_DIFFERS) {
 			fprintf(stderr, "XFS_IOC_FILE_EXTENT_SAME: %s\n",
 					_("Extents did not match."));
 			goto done;